This invention relates to household laundry processes having improved effectiveness for fabric bleaching and for simultaneous removal of stains and fugitive dyes.
U.S. Pat. No. 3,927,967 granted to Speakman on Dec. 23, 1975 related to a household washing and bleaching process for cotton fabrics utilizing photoactivating compounds, principally sulfonated zinc phthalocyanine, in the presence of visible light and atmospheric oxygen. Japanese Patent application OPI 50-113,479 assigned to the Proctor & Gamble Company, laid open to the public on Sept. 5, 1975, invented by Holcombe and Schultz, teaches the use of specific mixtures of sulfonated zinc phthalocyanine species, principally tri- and tetra-sulfonates, as preferred bleach photoactivators. In the foregoing references the detergent compositions utilizing sulfonated zinc phthalocyanine contained organic surfactant, anionic or nonionic and alkaline builder salt.
Belgian Pat. No. 840,348 invented by Wiers, granted on Oct. 4, 1976 discloses the use of zinc phthalocyanine tri- and tetra-sulfonates as bleach photoactivators in unbuilt liquid detergent compositions containing nonionic, anionic, zwitterionic, or ampholytic surfactants.
British Pat. No. 1,372,036 invented by Speakman and available to the public on Oct. 30, 1974 describes a washing machine provided with a source of visible light which irradiates wash liquor containing phthalocyanine photoactivator and fabrics.
U.S. Pat. Nos. 2,951,797; 2,951,798; 2,951,799 and 2,951,800, assigned to Monsanto Chemical Company and issued on Sept. 6, 1960 describe certain porphines as catalysts for the photo-oxidation of olefins.
References to carboxylated porphines have appeared in U.S. Pat. No. 2,706,199 issued Apr. 12, 1955, invented by Brentano et al, and C. R. Acad. Sci., Ser. C 1972, 275(11), 573-6 authored by Gaspard et al. See also Color Index No. 74320. References to aminosulfonyl porphines are West German OLS No. 2,057,194 laid open June 8, 1972, invented by Von der Eltz et al; British Pat. No. 613,781 accepted Dec. 2, 1948, invented by Mayhew; and British Pat. No. 876,691 published Sept. 6, 1961, issued to Geigy A.G. See also Color Index No. 74350. Other substituted porphines are disclosed in Austrian Pat. No. 267,711 issued Jan. 10, 1969, invented by Wimmer; French Pat. No. 1,226,094 published May 29, 1961, invented by Tartter et al; U.S. Pat. No. 2,670,265 issued Feb. 23, 1954, invented by Heyna et al; British Pat. No. 471,418 accepted Aug. 30, 1937, invented by Groves; and JCS 1938, 1-6 authored by Dent.
Two copending, commonly assigned patent applications filed in the name of the inventor of the instant invention disclose the use of many species of porphine photoactivatiors other than sulfonated phthalocyanines in combination with anionic, nonionic, semi-polar, ampholytic or zwitterionic surfactants. These are Philippine patent applications Nos. 20643 and 20644, both filed on Jan. 11, 1978. Both of these applications are hereby incorporated herein by reference.
The two applications referred to supra disclose new compositions that provide improved fabric whiteness by three different means: stain removal; oxygen bleaching of overall discoloration; and removal of fugitive dyes.
It has now been found that porphine photoactivators are especially useful in laundry baths in combination with cationic substances. These cationic substances are known to the laundry arts and, depending on the nature of their chemical structures, are useful in one or more of the following ways: as softeners or as electrostatic control agents for fabrics, as surfactants, or as germicidal or sanitation agents.
It is well known that cotton surfaces are negatively charged; and hence positively charged, i.e. cationic substances have a strong affinity for cotton fabrics and a strong tendency to adsorb or deposit thereon. In so doing they tend to bring down or co-adsorb other substances present in the laundry bath, such as the photoactivators of this invention. Greater deposition of photoactivator means greater effectiveness of a given amount of photoactivator which represents an economic advantage to both producer and consumer and more efficient utilization of natural resources, and which after use and waste disposal has a reduced impact upon the ecology of the environment.
The foregoing objects of this invention can be accomplished by any convenient laundry process which involves exposure of fabrics to a composition of this invention, and exposure to visible light and oxygen either simulaneously or thereafter. For example, photoactivator and cationic surfactant can be present together in the laundry pre-soak or alternatively in the laundry wash; or the photoactivator and a cationic fabric softener or antistatic agent can be present together in the laundry rinse; or the photoactivator and a cationic germicide can be present together in one of the foregoing washes or in a separate treatment bath. Exposure to light and oxygen can take place during the above recited processing step or can occur during a separate, subsequent, processing step such as drying out of doors, especially in direct sunlight as on a clothesline.